Stator of rotary electric machine and method for making the same

ABSTRACT

A stator core has a plurality of slots. Insulating members are formed into a cylindrical shape and are inserted into the slots. Axial ends of the insulating members are expanded respectively and deformation marks thinner than the other portion are formed respectively. Then, the insulating members are moved toward the expanded ends to position the deformation marks in the out of the slots. After that, the conductors are inserted into the slots from the expanded side of the insulating members. Therefore, insulation failure at the portions of the deformation marks is prevented.

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application is based on Japanese Patent Application No.Hei11-106914 filed on Apr. 14, 1999, the contents of which is incorporatedherein by reference.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to a stator of a rotary electricmachine having an improved dielectric strength at an edge of an axialinlet of a slot and a manufacturing method of the same.

[0004] 2. Description of Related Art

[0005] It is known that a construction is disclosed in JP 58-157349A forimproving a dielectric strength at an edge of a slot formed on a statorof rotary electric machine. In this prior art, wavy creases arepreviously formed on a portion of an insulating member where theinsulating member contacts an edge of a slot. After that, an end portionof the insulating member extended from the slot is heated and expanded.As a result, easiness for inserting a conductor into the slot isimproved, and insulation is maintained by inserting the insulatingmember to separate the conductor and the edge.

[0006] However, in the prior art, a heating and forming die is pressedon the stator core when the end portion is heated and expanded. Theinsulator is pressed on the edge of the slot, and a thickness isdecreased. Therefore, there is a possibility of insulation failure ifthe conductor is compressed between the die and the edge of the slot andis deformed.

SUMMARY OF THE INVENTION

[0007] The present invention addresses these drawbacks by providing animproved stator arrangement.

[0008] It is therefore an object of this invention to provide a statorhaving improved dielectric strength at the edge of the slot and amanufacturing method.

[0009] According to the present invention, an expanded end is formed onan insulating member. The insulating member is moved toward a side ofthe expanded end before a conductor is inserted from the expanded end.

[0010] Therefore, an easiness to insert the conductor is improved due tothe expanded end. An additional damage on the deformation mark isprevented when the conductor is inserted. Therefore, an insulationfailure at a deformation mark is prevented.

[0011] It is preferred that the deformation mark is positioned in theout of the slot after a conductor is inserted. In this construction ofthe stator, an additional damage on the deformation mark is preventedduring the conductor is inserted. A thickness of the insulating memberpositioned between an edge of a slot and the conductor is maintainedthicker than the thinned deformation mark.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Other features and advantages of the present invention will beappreciated, as well as methods of operation and the function of therelated parts, from a study of the following detailed description, theappended claims, and the drawings, all of which form a part of thisapplication. In the drawings:

[0013]FIG. 1 is a perspective view showing a stator core and aninsulating member of an embodiment of the present invention;

[0014]FIG. 2 is a perspective view showing a shape of a conductorinserted in to the stator core;

[0015]FIG. 3 is a side view showing an expanding process of theinsulating member;

[0016]FIG. 4 is a side view showing an expanding process of theinsulating member;

[0017]FIG. 5 is a side view showing an expanding process of theinsulating member;

[0018]FIG. 6 is a side view showing an expanding process of theinsulating member;

[0019]FIG. 7 is a side view showing an expanding process of theinsulating member;

[0020]FIG. 8 is a side view showing a pushing up process of theconductor;

[0021]FIG. 9 is a side view showing a pushing up process of theconductor;

[0022]FIG. 10 is a side view showing an inserting process of theconductor;

[0023]FIG. 11 is a side view showing an inserting process of theconductor;

[0024]FIG. 12 is a side view showing a form after the insertion of theconductor is completed;

[0025]FIG. 13 is a sectional view in the circumferential direction ofthe stator core showing the insulating member and the stator core; and

[0026]FIG. 14 is a sectional view in the circumferential direction ofthe stator core showing the insulating member and the stator core.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0027] An embodiment of the invention will be described with referenceto the drawings.

[0028] A stator has a cylindrical stator core 1, a plurality ofinsulating members 2 and a plurality of conductors 3. Each insulatingmember 2 is made of a sheet material. Each conductor 3 is shaped as aU-shape. The stator core 1 is formed by laminating thin silicon steelsheets. A plurality of slots 4 are formed on the stator core 1 at evenintervals. Each slot 4 has an opening 4 a at an inside of the statorcore 1 and openings at both of axial sides. The stator core 1 is formedto accommodate a three-phase stator coil. The insulating member 2 may bemade of, for instance, an insulating paper or a nonwoven fabric sheet.

[0029] As shown in FIG. 2, the U-shaped conductor 3 is a copper wirehaving a rectangular cross section corresponding to the slot 4. Theconductor 3 has accommodated portions 3 a to be accommodated into theslots 4, a turn portion 3 b connecting the accommodated portions 3 a andconnecting ends 3 c to be connected to the other conductor. The twoaccommodated portions 3 a are respectively inserted into the slots 4spaced apart a predetermined pitch. After that, the two connecting ends3 c of the U-shaped conductor 3 are respectively twisted in apredetermined direction for a predetermined pitch. After that, one ofthe connecting ends 3 c is connected to another one of the connectingends 3 c. Then, the stator coil is produced. In this construction, oneof the accommodated portions 3 a and the turn portion 3 b are connectedvia a bent portion 3 d.

[0030] Next, the inserting process and the expanding process of theinsulating member 2 will be described with reference to FIGS. 3 through7.

[0031] At first, longitudinal side edges of the sheet-shaped insulatingmember 2 are overlapped with each other by rounding the sheet-shapedinsulating member 2 into cylindrical shape. Then, an overlapping portion2 a is formed. The cylindrical insulating member 2 is inserted into theslot 4 from one axial end of the slot 4 so that the overlapping portion2 a is positioned to oppose an inner surface of the slot 4. In thisembodiment, the overlapping portion 2 a is positioned in a radialoutside. Each of the insulating members 2 provides an inner cavity forreceiving and accommodating a conductor. Therefore, as shown in FIG. 3,the cylindrical-shaped insulating members 2 are disposed in the slots 4to form a line.

[0032] Next, a former 5 heated to a predetermined temperature is pressedon ends of the insulating members 2 protruding from the slots 4. Theformer 5 has a plurality of former dies 5 a integrally connected in araw. Each of the former dies 5 a has a conical shape. In thisembodiment, each of the former dies 5 a is shaped as a quadrangularpyramid. A tip 5 b of the die 5 a has a shape corresponding to a shapeof the slot 4 to be able to be inserted into the slot. The former dies 5a are located so that the former dies 5 a are inserted into alternateslots 4 simultaneously. The former dies 5 a may be arranged to insertevery third slots or the like.

[0033] As shown in FIG. 4, the former 5 in which the former dies 5 a areheated to the predetermined temperature is moved by a driving devicewhich is not shown so that the former dies 5 a are contacted with theends of the insulating members 2. As shown in FIG. 5, each of theinsulating members 2 protruding from the slots 4 is compressed betweenthe former die 5 a and an edge formed along an axial opening of the slot4. Each of the ends of the insulating members 2 is expanded as a funnelshape. Therefore, expanded ends 2 b are formed.

[0034] In the above-described process, the insulating member 2 ispressed on the edge 4 b formed between the axial end surface of thestator core 1 and the inner surface of the slot 4. Therefore, adeformation mark 2 c, being thinner than the other portion, is formed ona portion where the insulating member 2 is compressed between the formerdie 5 a and the edge 4 b. The driving device moves the former 5 upwardlyafter the ends of the insulating members 2 are expanded as shown in FIG.6. The former 5 is moved for a slot in the circumferential direction ofthe stator core so that the former 5 is positioned above the insulatingmembers 2 in which the ends are still not processed. After that, theformer 5 is moved downwardly again, and is pressed on the insulatingmembers 2 to process them as shown in FIG. 7. Therefore, the ends of theinsulating members 2 are processed at an above-described expandingprocess. As a result, the stator core 1 equipped with the insulatingmembers 2 having the expanded ends is obtained as shown in FIG. 1.

[0035] Next, a pushing-up process of the insulating member 2 and aninserting process of the conductors into the slots 4 will be describedwith reference to FIGS. 8 through 12.

[0036] At first, the insulating members 2 are moved for a predetermineddistance by being pushed from the other ends of the insulating members2, that is, from the ends which are not processed by the heating andforming process as shown in FIGS. 8 and 9. The pushing-up process of theinsulating members 2 is carried out by using a support plate 6 and adriving motor which is not shown. The process includes a step forbringing the support plate 6 to contact with the other ends of theinsulating members 2, and a step for pushing the support plate 6 by thedriving motor to push all of the insulating members up simultaneously.

[0037] A plurality of U-shaped conductors 3 are inserted into boresdefined by the insulating members 2 in the slots 4. The conductors 3 areinserted from the expanded ends of the insulating members 2 after thepushing-up process of the insulating member 2 is completed as shown inFIG. 10. At this time, the two accommodated portions 3 a of the U-shapedconductor 3 are accommodated into the slots 4 spaced apart apredetermined magnetic pole pitch respectively. The support plate 6supports the other ends of the insulating members 2 even when theconductors 3 are inserted into the slots 4. The process of inserting theconductors 3 into the slots 4 is progressed until the ends of theconductors 3 contact with the support plate 6.

[0038] After the ends of the conductors 3 contact with the support plate6, the conductors 3 are moreover inserted with releasing a support bythe support plate 6. In this embodiment, the support is released bymoving the support plate 6 back synchronously with an insertion of theconductor. The conductors 3 are inserted until the bent portions 3 d ofthe conductors 3 are rested on the edges 4 b of the slots 4.

[0039] An appearance shown in FIG. 12 is obtained after the insertingprocess of the conductors 3 is completed. The deformation marks 2 c areplaced on an out of the slots 4 when the insertion of the conductor 3 iscompleted.

[0040] The connecting ends 3 c of one conductor 3 are bent in anopposite circumferential directions to respectively make an electricconduction with the other conductor 3 spaced apart the predeterminedmagnetic pole pitch. The two connecting ends 3 c of different conductors3 are joined. As a result, the conductors 3 construct the stator coil.

[0041] As shown in FIG. 13, the portion of the insulating member 2opposing to the edge 4 b of the slot 4 is thinned as the deformationmark 2 c, because it is compressed between the edge 4 b and the former5. This thinned deformation mark 2 c is moved to the out of the slot 4at the pushing-up process of the insulating member 2. In the insertingprocess of the conductor 3, the conductor 3 is inserted until the bentportion 3 d contacts with the edge 4 b of the slot 4. Therefore, theinsulating member 2 is pressed on the edge 4 b of the slot 4 by the bentportion 3 d of the conductor 3.

[0042] However, the deformation mark 2 c has been pushed out to the outof the slot 4. Therefore, a portion pressed on the edge 4 b by theconductor 3 is different from the portion of the thinned deformationmark 2 c. As a result, an insulation failure between the conductor 3 andthe stator core 1 at the portion of the deformation mark 2 c isprevented.

[0043] In this embodiment, the support plate 6 supports the insulatingmembers 2 at the ends not expanded. Therefore, it is prevented that thedeformation mark 2 c is pushed back to the edge 4 b of the slot 4 again.This is effective to maintain the insulation.

[0044] In this embodiment, the forming dies 5 a each shaped into thequadrangular pyramid expand the ends of the insulating members 2.Accordingly, the ends of the insulating members 2 can be easily expandedonly by pressing the heated former die 5 a. Further, it is possible toimprove easiness to insert the conductors 3 into the slots 4 byexpanding the ends of the insulating members 2.

[0045] In this embodiment, the former 5 has the plurality of former dies5 a which are integrally connected in a line. The former 5 isconstructed to be able to provide the heating and forming process to theplurality of insulating members 2 simultaneously. Therefore, it ispossible to shorten a man-hour for the manufacturing process.

[0046] In this embodiment, the former 5 can be inserted into the slots 4alternately. Therefore, the expanding process is easily carried outwithout a collision of adjacent former dies 5 a, even when the expandingprocess is carried out on the stator core 1 having a large number ofslots provided at narrower intervals therebetween.

[0047] In this embodiment, the overlapping portion 2 a is formed byoverlapping the ends of the sheet-shaped insulating member 2 formed intothe cylindrical shape. The insulating member 2 covers and fills theinside opening 4 a of the slot 4. The overlapping portion 2 a ispositioned to oppose to the radial outside wall in the slot 4 and issandwiched between the conductor 3 and the inner surface of the slot 4.Therefore, it is possible to maintain the insulation certainly evenunder a strong vibration of the vehicular AC generator.

[0048] In this embodiment, the expanding portion 2 b is formed as thefunnel shape. Alternatively, a shape having steps, a shape having aflange, a shape having expanded pleats or the like can be used as analternative to provide similar functions and effects described above.

[0049] Although the present invention has been described in connectionwith the preferred embodiments thereof with reference to theaccompanying drawings, it is to be noted that various changes andmodifications will be apparent to those skilled in the art. Such changesand modifications are to be understood as being included within thescope of the present invention as defined in the appended claims.

What is claimed is:
 1. A method for manufacturing a stator of a rotaryelectric machine, the method comprising: inserting insulating memberinto a slot formed on a stator core of the stator, said insulatingmember providing a inner cavity for accommodating a conductor; expandingend of said insulating member protruding from said slot; moving saidinsulating member for a predetermined distance toward a side of said endexpanded in said expanding process; and inserting conductor into saidcavity from said end expanded in said expanding process.
 2. A method formanufacturing a stator of a rotary electric machine, according to claim1, wherein: said end is expanded by using a former being heated, saidformer being pressed on said end.
 3. A method for manufacturing a statorof a rotary electric machine, according to claim 2, wherein: said formercomprises a conical-shaped former die.
 4. A method for manufacturing astator of a rotary electric machine, according to claim 3, wherein: saidformer comprises a plurality of former dies.
 5. A method formanufacturing a stator of a rotary electric machine, according to claim2, further comprising: a plurality of slots and a plurality ofinsulating members therein, and wherein said former expands a pluralityof ends by expanding a part of said ends, moving in a circumferentialdirection, and expanding another of said ends.
 6. A method formanufacturing a stator of a rotary electric machine, according to claim1, wherein: said conductor inserting process comprises, starting aninsertion of said conductor while said insulating member is axiallysupported, releasing a support of said insulating member, and continuingsaid insertion.
 7. A method for manufacturing a stator of a rotaryelectric machine, according to claim 1, wherein: said insulating memberhas an overlapping portion formed by overlapping with two ends of saidinsulating member each other, said overlapping portion being positionedto oppose an inner wall surface of said slot.
 8. A method formanufacturing a stator of a rotary electric machine, according to claim7, wherein: said overlapping portion is positioned in a radial outside.9. A stator of a rotary electric machine comprising: a stator corehaving a slot having an opening in a radial inside; and an insulatingmember formed into a cylindrical shape and disposed in said slot;wherein, said insulating member having an expanded end thereon, and saidexpanded end being positioned to have a predetermined distance from anedge of said slot.
 10. A stator of a rotary electric machine, accordingto claim 9, wherein: said expanded end is formed on only one end of saidinsulating member.
 11. A stator of a rotary electric machine, accordingto claim 9, wherein: said insulating member has an overlapping portionformed by overlapping with two ends of said insulating member eachother, said overlapping portion being positioned to oppose an inner wallsurface of said slot.
 12. A stator of a rotary electric machine,according to claim 11, wherein: said overlapping portion is positionedin a radial outside.
 13. A stator of a rotary electric machine,according to claim 9, further comprising: a plurality of slots, aplurality of insulating members therein, and a U-shaped conductor havinga turn portion located in an axial side where said expanded end isprotruded.
 14. A stator of a rotary electric machine, according to claim13, wherein: said U-shaped conductor further comprises accommodatedportions accommodated in said slots and said turn portion connectingsaid accommodated portions, wherein said insulating member has adeformation mark formed by a former pressed on said insulating member,said insulating member being pressed on an edge by a bent portion formedbetween said accommodated portion and said turn portion of saidconductor, and said deformation mark being positioned to have apredetermined distance from said edge.